Electrical storage batteries must often operate in hostile environments, especially those environments of high temperature. The electrical current output of such batteries and the reliability of the batteries are strongly dependent upon the temperature of the battery and high temperature environments can very substantially adversely affect the operation and reliability of the battery. High temperatures can cause failure of the grid system of the electrode plates and, hence, failure of the battery.
While the present invention is broadly applicable to a cover for batteries, the above-noted hostile environment and, particularly, high temperatures of the battery are increasingly encountered in modern automobiles, especially in hot climates, and for the sake of conciseness, that particular application of the present cover will be discussed hereinafter, although it is to be understood that the present invention is not limited thereto.
In this regard, there is a considerable effort in the art to downsize modern automobiles. This downsizing has resulted in more and more restrictions on space available under the hood of an automobile for placement of the automobile battery. The position of the battery placement is often referred to in the art as the "real estate" occupied by the battery, and in view of the shrinking total real estate under the hood of a modern automobile, the battery has been placed closer and closer to other operating mechanisms under the hood. Many of those operating mechanisms generate substantial heat, e.g. the manifold, and when the real estate of the battery is in close proximity to such heat-generating devices, in operation of the automobile, the battery may be heated by those devices to unacceptable temperatures. Also, and just as importantly, modern automobiles have smaller and smaller air-intake grills, or no grill at all, and this engenders increased and severe operational temperatures and the resulting reliability difficulties. This is especially true when the automobile is operated in hot climates.
In contrast to the modern automobile, older larger automobiles have considerable total real estate under the hood, and the real estate occupied by the battery could be spaced far from any heat-generating devices. Those older automobiles also had generous air-intake grills. Thus, the air flow around the battery during movement of the automobile was more than sufficient to keep the battery cool and to keep the battery at essentially the same temperature throughout. This luxury of real estate and large grills is no longer available in modern automobiles, and increasing difficulties have been encountered in the operation and reliability of the battery, as the battery real estate is moved closer and closer to such heat-generating devices and grills shrink or disappear.
Some automobile manufacturers have addressed this problem by moving the battery from under the hood to, for example, under the rear seat. However, while this solves the problem of overheating of the battery, it engenders other problems of considerable difficulty, e.g. lack of easy access, the possibility of toxic battery fumes entering the passenger compartment, and the difficulty of servicing that battery. For these reasons, it is particularly desired to retain the battery real estate under the hood of the automobile, but to, at the same time, mitigate the difficulties encountered in the higher temperature environments.
To this end, the art has proposed battery covers, but prior art battery covers have not been successful and have not been widely adopted in automobile manufacture. Some of such battery covers are simply insulating blankets, but such insulating blankets have the difficulty of being damaged by ordinary operation and maintenance of the motor vehicle, e.g. damaged by oil and water, or damaged in removing and replacing the blankets from the battery when servicing the battery. The blankets, being bulky, also occupy too much real estate and are unsightly.
The art has also proposed rigid molded plastic battery boxes in which a top lid or portion of the box is removable for insertion of the battery. While these battery boxes do provide some measure of protection to the battery, the molded plastic boxes do not have significant thermal insulation, and the thermal problem, noted above, continues to exist. This is true even with such boxes which have double walls with an insulating air space therebetween. In addition, in order to slip the battery in and out of the battery box, there must be sufficient clearance between the inside walls of the battery box and the battery for ease of that movement. This results in the total real estate occupied by the battery and battery box to be greater than the real estate occupied by the battery alone, and such significant increase in real estate is not desirable in modern automobiles.
While such a battery box could be constructed of an insulating material, such insulating material must be of reasonable thicknesses in order to provide substantial insulation, e.g. at least one quarter inch or one half inch thick, and such an insulated battery box substantially further increases the total real estate occupied by the battery and insulated battery box, which is undesirable in view of the efforts in the art to conserve the real estate under the hood. Further, while such an insulated battery box could prevent heat passing from a nearby heated device, e.g. a manifold, to the battery, that same insulated battery box will, to a large measure, reduce the cooling effect for the battery by air flowing over that battery box when the automobile is moving. This is true even when an air duct is directed toward the battery, since the cooling effect thereof is not sufficient and the cost of such ducting in undesired. Further, ducting systems for cooling effectively operate only when the automobile is moving at high speeds. In a sense, therefore, the insulated battery box is counterproductive in cooling the battery and maintaining the battery at proper operating temperatures.
It would, therefore, be of substantial advantage in the art to provide a protective and insulating cover for a battery which not only prevents the battery from being excessively heated by adjacent heating devices, but also allows the battery to be cooled, in the normal manner, by air passing over the battery cover during movement of the automobile and by convection when the automobile is travelling at low speeds or is stationary. It would further be a very substantial advantage to the art to provide the above with, essentially, little increase in the real estate required for the battery and battery cover.